1. Field of the Invention
The present invention relates to a method for classifying a occupant weight of a vehicle and, more particularly, to a method for classifying an occupant weight of a vehicle capable of shortening an occupant weight classification time when a change in a weight of an occupant is sensed according to occupant's occupancy and vacancy of a vehicle seat and lengthening an occupant weight classification time when a change in a weight of the occupant is sensed according to a movement of the occupant.
2. Description of the Related Art
FIG. 1 shows an airbag deployment situation of a general vehicle and FIG. 2 is a perspective view showing an occupant weight sensor for sensing a weight of an occupant.
In general, an airbag 6 is installed at a front side or at the side in a vehicle in order to safely protect the occupant by using its cushion operation in occurrence of a vehicle collision accident.
The airbag 6 includes a driver airbag (DAB) installed in a steering wheel to protect the front side of a driver seated in a driver's seat and a passenger airbag (PAB) installed at an instrument panel to protect the front side of an occupant seated in the passenger's seat.
In addition, recently, in order to protect the occupant against a side collision, as well as to protect the front side of the occupant, a side airbag is installed in the backrest of the vehicle seat or a door trim, a curtain airbag is mounted in a loop rail part and deployed in a curtain state between the occupant and a side window, and a side protecting airbag such as an ITS (Inflatable tubular Structure) is mounted at an inner side a head liner at an upper side of a door of the front seat.
Since the airbag 6 is instantaneously inflated, if its deployment force is excessive, it would inevitably do harm to the occupant. Thus, a system is under development to sense the weight of the occupant and classify the occupant based on the sensed weight in order to deploy the airbag with a suitable deployment force according to a type of each occupant based on physical conditions to thereby protect various occupants each with various physical conditions.
A weight sensor 4 for sensing the weight of the occupant is installed at a lower side of the driver's seat or the passenger's seat and senses the weight of the seated occupant, and a weight classification system for classifying the occupant based on the weight value sensed by the weight sensor and including a controller (not shown) is provided in the vehicle.
Namely, when the weight of the occupant seated in the driver's or the passenger's seat 2 is sensed through the weight classification system, the weight is classified into an ‘empty’, ‘child’ and ‘adult’ weight class and whether to deploy the airbag and its deployment force are determined accordingly.
FIG. 3 illustrates a method for classifying an occupant weight of a vehicle in accordance with a related art. In the related art, once an occupant gets in to a vehicle, the occupant is classified into a weight class [0] and a weight class [1] based on a first reference value (Th1) and classified into the weight class [1] and a weight class [2] based on a second reference value (Th2) according to its weight sensed by the weight classification system. As the occupant is gets in to or off the vehicle, a change in the weight is sensed and the weight class is changed accordingly.
However, if the weight of the occupant is close to the reference value serving as a reference for discriminating each weight class, the weight would be frequently changed between the weight classes adjacent to the reference value according to vehicle vibration and a movement of the occupant. Then, a warning light would be repeatedly lighted on and off according to the weight classification, which interferes driver's concentration to driving.